SERVICE MANUAL
LUBRICATING OIL PUMP, OIL FILTERS & COOLER
Section 8
Figure 3. - Crankcase Front Cover and Lube 011
Suction Tube
1. Oil suction tube
2. Crankcase front cover
The pump assembly with an "O" Ring sealed porting
plate (1, Fig. 4) is fastened to the crankcase front cover
so the forward end of the crankshaft passes through the
pump. A splined sleeve (3, Fig. 4) on the crankshaft
engages the inner rotor (2, Fig. 4). This drives the pump
at engine speed.
Figure 4. - "GEROTOR" Lubricating Oil Pump
1. Porting plate
5. Pump housing
2. Inner rotor
6. Outer rotor
3. Spline
7. Oil intake
4. "0" Ring/Seal Ring
8. Pressure port
The inner rotor (2, Fig. 4) is concentric to the crankshaft,
whereas the outer rotor (6, Fig. 4) is not. There are 14
spaces in the outer rotor and only 13 teeth on the inner
rotor. As the pump rotates, oil from the pan enters the
pump on one side (7, Fig. 4) as the teeth leave the outer
rotor. The oil is carried to the other side of the pump in
the spaces and as the teeth re-enter the spaces, the oil
is forced out the pressure port (8, Fig. 4) on its way to the
oil cooler.
A lip-type front engine oil seal is pressed into the pump
housing and the housing is dowel pinned to the front
cover which automatically aligns the pump and seal.
Two different oil pumps are used; one for the
Turbocharged
engines
and
one
for
the
naturally
aspirated models. The basic difference is the width of
the pump which affects the capacity. The Turbocharged
engines, with two cooling jets per piston, use the larger-
capacity pump.
Lubricating Oil Filters:
The oil filters (1, Fig. 5) are the full-flow type and are
interconnected by common internal passages in the
crankcase. One passage is for the inlet (3) and one for
the outlet (5). The filters do not have internal by-pass
valves. Instead, one by-pass valve (4) located in the filter
base (2) controls the oil flow through the filters.
Figure 5. - Oil Filters and Filter Base
1. Oil filters
2. Filter base
3. Inlet passage
4. By-pass valve
5. Outlet passage
CGES-185-3
PRINTED IN UNITED STATES OF AMERICA
Page 3
